Deep Neck Space Infections: A Study of 76 Cases.

INTRODUCTION
Deep neck space infections (DNSI) are serious diseases that involve several spaces in the neck. The common primary sources of DNSI are dental infections, tonsillar and salivary gland infections, malignancies, and foreign bodies. With widespread use of antibiotics, the prevalence of DNSI has been reduced. Common complications of DNSI include airway obstruction, jugular vein thrombosis, and sepsis. Treatment principally comprises airway management, antibiotic therapy, and surgical intervention. This study was conducted to investigate the age and sex distribution of patients, symptoms, presentation, sites involved, bacteriology, and management and complications of DNSI.


MATERIALS AND METHODS
This retrospective study was performed from October 2010 to January 2013, and included 76 patients with DNSI. Patients of all age groups and gender were included. All parameters including age, gender, co-morbidities, presentation, site, bacteriology, complications, and required interventions were studied.


RESULTS
In our study, the majority of patients were in the 31-50-year age group. Males accounted for 55.26% of the sample and females for 44.74%, with a male:female ratio of 1.23. Most of the patients were from a rural background. Diabetes was found as a co-morbid condition in 10.52% cases. Neck pain was the most common symptom, identified in 89.47% cases. The most common etiological factor was odontogenic infection (34.21%), followed by tonsillar and pharyngeal infection (27.63%). The most common presentation was Ludwig's angina (28.94%), followed by peritonsillar abscess and submandibular abscess. In 50% of cases, Streptococcus and Staphylococcus were found in the culture. Surgical intervention was carried out in 89.47% cases. Emergency tracheotomy was required in 5.26% cases.


CONCLUSION
DNSI can be life-threatening in diabetic patients, the immunocompromised, and elderly patients, and special attention should therefore be given to these groups. Early diagnosis and treatment is essential to prevent complications. All patients must be treated initially with intravenous antibiotics, with treatment subsequently updated based on a culture and sensitivity report. Due to poor oral hygiene, lack of nutrition, smoking and chewing of beetle nut and tobacco, odontogenic infections are the most common cause of DNSI. Thus, DNSI could be prevented by making the population aware of dental and oral hygiene and offering regular check-ups for dental infections.


Introduction
Deep neck space infection (DNSI) refers to an infection in the potential spaces and fascial planes of the neck, either with abscess formation or cellulitis (1). At least 11 deep spaces are part of the complex structure formed by the facial planes, providing possible infection sites. Based on their relationship with the hyoid bone, the deep spaces may be classified as follows: spaces localized above the hyoid level (peritonsillar, submandibular, parapharyngeal, buccal, parotid, masticatory/ temporal); spaces that involve the entire circumference of the neck (retropharyngeal, danger space, prevertebral and carotid); and the anterior or pretracheal visceral space, below the hyoid bone (2). DNSI are bacterial infections originating from the upper aerodigestive tract and involving the deep neck spaces (3). The most common primary sources of DNSI are the dentition, tonsils, salivary glands, foreign bodies, and malignancies. DNSI often occur following preceding infections such as dental caries, tonsillitis, pharyngitis, trauma to the head and neck, or among intravenous drug abusers. Infections originating from teeth or their supporting structures, known as odontogenic infections, are among the most common diseases in the oral and maxillofacial region, especially in developing countries (4). Previously, before the advent of antibiotics, tonsillar and peritonsillar infections were the source of infection in 70% cases of DNSI (5); but now the most common cause is considered to be dental in origin (6). DNSI are usually polymicrobial in nature. Streptococci, Peptostreptococcus species, Staphylococcus aureus, and anaerobes are the most commonly cultured organisms from DNSI (7,8). Clinical manifestations of DNSI depend on the spaces involved, and include pain, fever, malaise, fatigue, swelling, odynophagia, dysphagia, trismus, dysphonia, otalgia, and dyspnea (9).
A rapidly progressive course of DNSI with a fatal outcome may be seen, especially in immunocompromised patients with diabetes mellitus, chemotherapy, steroid therapy, or HIV infection (2). In past, these infections were fairly common; however, with the advent of broad spectrum antibiotics, the incidence of these infections has decreased. Despite the extensive use of antibiotics, DNSI still remains serious and is associated with significant morbidity. These infections are potentially life threatening and spread rapidly, leading to severe complications. Potentially life-threatening complications have been reported to occur at a rate of 10-20%, even in recent literature on DNSI cases (10,11). Common and potentially life-threatening complications include airway obstruction, jugular vein thrombosis, descending mediastinitis, pericarditis, pleural empyema, cavernous sinus thrombosis, sepsis, respiratory distress, disseminated intravascular coagulation (2), pleuropulmonary suppuration, and hematogenous dissemination to distant organs (12).
Treatment of DNSI includes antibiotic therapy, airway management and surgical intervention. Management of DNSI is traditionally based on prompt surgical drainage of the abscess followed by antibiotics or nonsurgical treatment using appropriate antibiotics in the case of cellulitis (13). Proper diagnosis and prompt management can effectively overcome the disease and provide a cure without complications. However, for this to be possible, otorhinolaryngologists must have detailed knowledge of the presentation, etiology, investigations and access to appropriate medical and surgical interventions. The main aim of our study was to share our experience in terms of presentation, clinical trends, common sites involved, bacteriology, management, complications, and outcomes.

Materials and Methods
In this retrospective study, 76 patients who were admitted and treated for DNSI in the ear, nose and throat (ENT) department from October 2010 to January 2013 were included. We excluded patients who had an infection related to inhalant injuries or due to any malignancy. A total of 76 cases of DNSI met our inclusion criteria. Patients of all age groups and both genders were included. All parameters including age, gender, comorbidities, symptoms, site involved, bacteriology, culture growth, type of intervention required, complications, and outcome were studied. All patients were initiated on treatment with amoxicillin, clavulanate, and metronidazole; the treatment regimen was later modified based on a culture and sensitivity report.

Results
We evaluated 76 DNSI inpatients. The mean age of the patients was 33.2 years, with a minimum age of 4 years and a maximum age of 72 years. The majority of patients were in the 31-40-year age group, followed by the 41-50-year age group.   In the majority of cases, the etiological factor was odontogenic in origin (26 patients, 34.21%). The etiological factor was unknown in seven patients (9.21%) ( Table. 3). In terms of management, incision and drainage, needle aspiration or both were performed in 68 patients (89.47%). Eight patients (10.53%) were managed by medical treatment alone. All 76 patients were given broad spectrum intravenous antibiotics, which were later updated based on culture and sensitivity report. Forty-four patients (57.89%) required an external approach for incision and drainage. Fifteen patients (19.74%) needed intra-oral aspiration, while nine patients (11.84%) required both approaches. Mastoidectomy was performed in one (1.31%) of the patients. Four patients (5.26%) required emergency tracheotomy for airway management.
Complications were encountered in a few patients. Four patients had upper airway obstruction, three had septic shock, two had internal jugular vein thrombosis, two had skin necrosis and one had mediastinitis. One patient died during his hospital stay due to an unrelated systemic complication. The mean hospital stay was 4.2 days, with a minimum of 3 days and a maximum of 15 days.

Discussion
The widespread use of antibiotics has decreased the incidence of DNSI, but it remains a fairly common problem. In our study, 76 DNSI patients were included and all were admitted to the hospital for treatment. The management and diagnosis of DNSI is still a challenge for otorhinolaryngologists.
Evaluation of variables relating to life-threatening diseases is very important. In our study, the majority of patients were seen in their third and fourth decade. This correlates with the studies by Parischar et al. and Meher et al. in which 50% and 60% patients were in the third and fourth decade of life, respectively (6,14). In our study, a male predominance was seen, which is consistent with studies by Sethi et al. Meher et al. and Parischar et al. all of which showed male preponderance (6,14,15). Further, in our study, diabetes was associated with 10.52% patients, which is very low compared with the study of Huang et al which reported 30.3% patients of diabetes mellitus (8). Twenty-eight of our patients were tobacco chewers. This results in poor oral hygiene and is reported to affect the host's vulnerability to systemic diseases by the formation of subgingival biofilms acting as reservoirs of Gramnegative bacteria, and through the periodontium acting as a reservoir of inflammatory mediators (16 (8,17,20). Studies by Sethi et al. and Har-El G et al. also showed the major cause of DNSI to be dental in origin (15,21).Thus, our study results are consistent with those of these previous studies. The most common presentation of DNSI in our study was Ludwig's angina (28.94%), followed by peritonsillar abscess (23.68%), submandibular abscess (18.42%), parapharyngeal abscess (10.52%), and retropharyngeal abscess (5.26%). Ludwig's angina, peritonsillar abscess, and anterior neck abscess accounted for approximately 56% of our cases, which is consistent with the studies by Afshin et al. and Khode et al. with about 60% cases with a similar presentation (22,23). Peritonsillar abscess and submandibular abscess were the second and third most common presentation in our study, which correlates with study results from Pariscar et al. and Stalfor et al. with peritonsillar and submandibular as the second and third most common presentation (6,24).
Streptococcus species were the most common cultured organism in our study, which is consistent with the studies of Ridder et al. Parischar et al. Mumtaz et al. and Gidley et al. (6,[25][26][27]. In 11 patients (16.17%), no organism was cultured, which was probably due to use of antibiotics at the time the cultures were sent. A contrast CT scan is the most appropriate imaging tool, not only for the diagnosis of deep neck space infections, but also to show the extent of disease. CT scans are not only beneficial in differentiating between cellulitis and abscesses, but also have an important role in the evaluation of serious complications. A CT scan also helps to decide whether a surgical intervention is indicated, as patients with radiological evidence of cellulitis respond well to medical treatment, whereas those with abscess have a higher incidence of complications and usually require surgical management due to the aggressive nature of this condition. Ultrasound also plays an important role in the detection of abscess formation (13,28). In our study, a CT scan was performed in 90.78% patients and ultrasound was performed in 5.26% cases.
Worldwide, management of DNSI usually involves early surgical drainage of purulent abscesses via an external incision (1,19,20). In our study, all patients were initiated on intravenous antibiotic therapy with amoxicillin, clavulanic acid, and metronidazole, which was later modified according to the culture and sensitivity report. In the case of a significant abscess on the CT scan, prompt open surgical drainage has been shown to be the most suitable technique for treating DNSI (8). In our study, surgical intervention was carried out in 89.47% of patients, which is consistent with the studies by Mumtaz (6,20,21,26). Airway management is challenging in patients with DNSI. Usual causes of airway compromise are laryngeal edema and pushing of the tongue upwards and backwards, especially in Ludwig's angina. In our study, tracheotomy was performed in 5.26% of cases, which is consistent with the study by Eftekharian et al. (20), in which tracheotomy was required in 8.8% cases. A tracheal intubation with rigid laryngoscopy may be difficult in these patients due to the possibility of distortion in the airway anatomy, tissue rigidity, and a limited access to the mouth. Thus, the tracheotomy must always be considered whenever there is respiratory difficulty. Sometimes attempting intubations can worsen an already damaged airway (29).

Conclusion
DNSI remains a common and challenging disease for clinicians, and should be treated on emergency basis. It is also very important to give special attention to high-risk groups such as diabetics, the elderly, and patients with underlying systemic diseases as the condition may progress to life-threatening complications. Early diagnosis and treatment is essential. Thus, all patients should be initiated on treatment with empirical intravenous antibiotic therapy, which should be updated later according to the culture and sensitivity report. All patients with a significant abscess on the CT scan require surgical intervention. Tracheotomy should be considered if airway protection is needed. In developing countries, lack of adequate nutrition, poor oral hygiene, tobacco chewing, smoking and beetle nut chewing has led to an increased prevalence of dental and periodontal diseases. In our study, odontogenic infections were the most common etiology for DNSI. Therefore, prevention of DNSI can be achieved by making the population aware of dental and oral hygiene and encouraging regular checkups for dental infections.